Pregnancy is one of the most amazing things you’ll experience. There’s nothing quite like growing a human inside your own body!

There are lots of pregnancy symptoms and side effects that are weird, but totally normal. Here are 15 strange facts about pregnancy that you might not know…

1. At around four months pregnant, your baby starts to urinate in the womb. And can you guess that pee goes? They drink it. Pretty disgusting, right?!

2. At the beginning of your pregnancy, your uterus is the size of a small peach. It stretches to the size of a watermelon by the end of pregnancy. That’s about 500 times its original size!

3. If you’re overweight or tall, you have a higher possibility of carrying multiples.

4. At around 9 to 12 weeks, your baby has all of his or her unique fingerprints!

5. At the very end of your pregnancy, your placenta is producing the same amount of estrogen that a non-pregnant woman does in three years!

6. Babies have been recorded doing a number of activities while inside the womb. From sucking their thumbs to waving “hi,” you might even be able to see in an ultrasound!

7. Nine out of 10 women undergo a shift in their skin tone during pregnancy.

8. Did you know that your heart grows during pregnancy? It’s because your heart is working hard to pumps more blood for your growing baby!

9. A few pregnant women lactate in their third trimester when they hear someone else’s baby crying.

10. Pregnant women have a sharper sense of smell. Wonder why? It’s to help them avoid foods they shouldn’t eat because of their growing baby.

11. Three out of 4 women form a “linea nigra” during pregnancy. The linea nigra is a dark, vertical line that runs down the stomach. For some women, this fades after giving birth. But, for some, it doesn’t.